遗留Java GAE本地服务器连接Cloud DB遇错求助（SDK 1.9.84）

环境背景 #

• 基于GCP的遗留Java代码库，使用appengine-api-1.0-sdk-1.9.84.jar
• 项目未使用Maven，WEB-INF/lib下的依赖jar包：

  appengine-api-1.0-sdk-1.9.84.jar
  appengine-api-labs.jar
  appengine-api-labs-1.9.76.jar
  appengine-api-stubs-1.9.76.jar
  appengine-gcs-client.jar
  appengine-jsr107cache-1.9.76.jar
  appengine-mapper.jar
  appengine-testing-1.9.76.jar
  appengine-tools-sdk-1.9.76.jar
  charts4j-1.2.jar
  guava-11.0.2.jar
  javax.inject-1.jar
  json-20190722.jar
  

问题历程 #

最初在Filter的init方法中配置CloudDatastoreRemoteServiceConfig以连接Cloud Datastore时，遇到错误：

GlobalDatastoreConfig has already been set

排查发现是静态代码块提前初始化了DatastoreService，于是将所有DatastoreServiceFactory.getDatastoreService()调用替换为Const.java中的静态方法：

private static boolean hasInit = false;
public static DatastoreService getDatastoreService() {
    if(!hasInit) {
        try {
            CloudDatastoreRemoteServiceConfig config = CloudDatastoreRemoteServiceConfig
                        .builder()
                        .appId(CloudDatastoreRemoteServiceConfig.AppId.create(CloudDatastoreRemoteServiceConfig.AppId.Location.US_CENTRAL, "gcp-project-id"))
                        .build();
            CloudDatastoreRemoteServiceConfig.setConfig(config);
            hasInit = true;
        } catch (Exception ignore) {}
    }
    return DatastoreServiceFactory.getDatastoreService();
}

该方法解决了初始化错误，但现在出现新的报错日志：

Dec 08, 2022 6:49:56 PM com.google.appengine.api.datastore.dev.LocalDatastoreService init
INFO: Local Datastore initialized: 
    Type: High Replication
    Storage: C:\Users\user\dev\repo\Celbux\core\Funksi179_NSFAS_modules\classes\artifacts\Funksi179_NSFAS_modules_war_exploded\WEB-INF\appengine-generated\local_db.bin
Dec 08, 2022 6:49:56 PM com.google.appengine.api.datastore.dev.LocalDatastoreService load
INFO: Time to load datastore: 20 ms
2022-12-08 18:49:56.757:WARN:oejs.HttpChannel:qtp1681595665-26: handleException / java.io.IOException: com.google.apphosting.api.ApiProxy$CallNotFoundException: Can't make API call urlfetch.Fetch in a thread that is neither the original request thread nor a thread created by ThreadManager
2022-12-08 18:49:56.762:WARN:oejsh.ErrorHandler:qtp1681595665-26: Error page too large: 500 org.apache.jasper.JasperException: com.google.apphosting.api.ApiProxy$RPCFailedException: I/O error

错误触发自以下代码行：

DatastoreService ds = Const.getDatastoreService();
Key ConstantKey = KeyFactory.createKey("Constants", 1);
Entity Constants1 = ds.get(ConstantKey); // <-- 报错行

目标需求 #

希望本地运行的代码直接连接Cloud Datastore而非本地模拟器，以便调试多个共享同一云数据库的应用，求有相关遗留SDK经验的解决方案。

内容的提问来源于stack exchange，提问作者James